|Tas Seasonal Rainfall Outlook: probabilities for Winter 2006, issued 25th May 2006|
Reduced winter rainfall favoured in parts of northern and central Tasmania
There is a moderate shift in the odds towards below average winter (June-August) rainfall across parts of northern and central Tasmania, the Bureau of Meteorology announced today. For the rest of the state, the chances of accumulating at least average rain during winter are close to 50%.
The pattern of winter rainfall odds is largely a result of above average temperatures in the Pacific Ocean. Conditions in the Indian Ocean are near normal and have little influence on the outlook.
For the June to August period, the chances of above median rainfall are between 30 and 40% over much of northern Tasmania, extending southwards through central Tasmania to the Derwent Valley (see map). This means that below average falls have a 60 to 70% chance of occurring.
So in years with ocean patterns like the current, six to seven winters out of 10 are expected to be drier than average in these regions, with three to four out of ten being wetter.
Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During winter, history shows this influence to be weakly consistent in most of Tasmania, reaching moderate only in patches (see background information).
The Southern Oscillation Index (SOI) has been generally positive recently, with values for February, March and April of zero, +14 and +15 respectively. However, values have recently dropped with the approximate SOI for the 30 days ending 21st May being zero.Most computer models indicate that neutral ENSO conditions are likely to remain in place for most of the remainder of 2006. However, it should be noted that model skill is at its lowest during autumn. For routine updates and comprehensive discussion on the latest data relating to ENSO, together with details on what the phenomenon is and how it has affected Australia in the past, please see the ENSO Wrap-Up.
Click on the map above for a larger version of the map. Use the reload/refresh button to ensure the latest forecast map is displayed.
|More information on this outlook is available from 9.00am to 5.00pm (EST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Hobart Office: (03) 6221 2043.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 22nd JUNE 2006